The invention disclosed and claimed herein relates to a tilt correction system for a vehicle and, more particularly, to a hydraulically-operated, tilt correction system which levels a vehicle during a turn-induced roll.
Generally, in the operational environment of the invention, there is found a vehicle such as an automobile having a body, four tires, two front and two rear, axles for mounting the front and rear wheels to the body, and a suspension connecting the vehicle body to the axles.
When a vehicle turns, the suspension permits the vehicle body to rotate about its longitudinal axis in response to the rolling force exerted on the body during the turn. Typically, vehicle passengers experience this effect as a tilt of the vehicle body, with the side of the body on the outside of the curve being relatively lower than the side of the body on the inside.
Anti-roll systems known in the art counteract vehicle roll by providing a lifting force acting between the vehicle body and suspension on the outside of the curve or a vehicle lowering force acting between the body and suspension on the inside turn side of the vehicle. Some anti-roll systems in the art provide complementary lifting and lowering forces simultaneously.
In the related patent applications, a system for roll compensation is taught in which a valved hydraulic signal generator provides a differential hydraulic signal indicative of vehicle roll. The hydraulic signal includes pressurizing and return components. Pairs of cylinder and piston assemblies are provided for roll correction at the rear and front wheels of the vehicle. The system includes a hydraulic circuit connected to the valved hydraulic signal generator and to the cylinder and piston assemblies for conducting the differential hydraulic signal to all of the cylinder and piston assemblies. In conducting the signal, the circuit provides the pressurizing potential of the signal to move the pistons in the cylinder and piston assemblies in complementary directions on either side of the vehicle. The piston directions counteract the roll of the vehicle and thereby level the vehicle when it turns. The systems include a tilt limitation means connected to the hydraulic circuit for limiting the maximum displacement of the pistons in the front wheel cylinder and piston assemblies, which limits the amount of roll correction afforded by the system.
Tilt limitation in these systems is afforded a cylinder and piston assembly with upper and lower ports and at least a third port between the upper and lower ports. When the piston moves a certain distance, the middle port is opened, providing a shunt to the hydraulic pressure moving the piston.
While the tilt-limited, anti-roll systems of the cross-referenced patent applications have met with general approbation, a need still exists for a very simple anti-roll system with tilt limitation which is easy to install and simple to manufacture, yet which retains advantages of the cross-referenced systems.